There was a big exhibition of Rodchenko stuff at the Hayward Gallery in London a couple of years ago. It was fascinating, although a lot of the prints were disappointing in the flesh as the style -- albumen prints, quite low contrast and 'soft' -- didn't match how I've often seen them in reproduction. The montages and collages were really interesting, as they had a lot of the originals, and they were much smaller than I was expecting. Smaller by far than you often see them printed.